The other thing that will reduce your choice is that the library service will have done a community profile of the area around each branch library, analysing it in terms of demographic etc. As a result of this, each library will probably be banded. A large central library will be Band A, meaning that its stock will be broader and will cater for more minority interests. A small branch library in a residential area will probably have been banded Band C, or something like that, and will have a stock profile drawn up that has a high proportion of fiction, and non-fiction mostly being popular subjects like gardening, cookery, and health.